If you cannot flash a ROM, you can still speed up the phone by enabling Developer Options and setting all "Animation scales" to 0.5x to make the UI feel twice as fast.
This is the most critical step. Without an unlocked bootloader, you cannot modify the system partitions.
You cannot flash custom recovery or images without an unlocked bootloader. (Note: Some US carrier variants like Verizon, AT&T, or TracFone may have permanently locked bootloaders that prevent this process).
If you cannot flash a ROM, you can still speed up the phone by enabling Developer Options and setting all "Animation scales" to 0.5x to make the UI feel twice as fast.
This is the most critical step. Without an unlocked bootloader, you cannot modify the system partitions.
You cannot flash custom recovery or images without an unlocked bootloader. (Note: Some US carrier variants like Verizon, AT&T, or TracFone may have permanently locked bootloaders that prevent this process).